Relative likelihood for life as a function of cosmic time

Journal article

Is life most likely to emerge at the present cosmic time near a star like the Sun? We address this question by calculating the relative formation probability per unit time of habitable Earth-like planets within a fixed comoving volume of the Universe, dP (t)/dt, starting from the first stars and continuing to the distant cosmic future. We conservatively restrict our attention to the context of “life as we know it” and the standard cosmological model, ΛCDM. We find that unless habitability around low mass stars is suppressed, life is most likely to exist near ∼ 0.1M ⊙ stars ten trillion years from now. Spectroscopic searches for biosignatures in the atmospheres of transiting Earth-mass planets around low mass stars will determine whether present-day life is indeed premature or typical from a cosmic perspective.

Authors: Loeb, A; Alves Batista, R; Sloan, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Institute of Physics
• Journal: Journal of Cosmology and Astroparticle Physics
• Volume: 2016
• Pages: 040
• Publication date: 2016-08-01
• Acceptance date: 2016-07-26
• DOI: 10.1088/1475-7516/2016/08/040
• ISSN: 1475-7516
• Keywords: star formation; habitable planets